1. Field of the Invention
The present invention relates to a vertical axis clothes washer having a bottom plate capable and more particularly to a system for mounting and driving the bottom plate selectively in either an angled or level orientation.
2. Description of Related Art
Typically, a conventional vertical axis automatic washer functions by loading fabric items or clothes to be washed into a vertically aligned wash basket disposed within a wash tub. Detergent and water are supplied into the tub and basket for forming a wash liquid such that the fabric items are completely submerged in wash liquid. A vertically orientated agitator centrally supported within the wash basket oscillates and causes the clothes to move in the wash liquid within the wash basket.
Automatic washers using vertical agitators generally require the use of a large amount of water, as much as 46 gallons to suitably wash one clothes load. This is due to the fact that for the oscillating agitator to properly apply mechanical energy to the clothes without damaging them, all of the fabric items must be substantially submerged in wash liquid. This complete submersion of the fabric items occurs during the wash cycle and each of the subsequent rinse cycles. Additionally, agitators have been know to apply mechanical energy to fabric items in a harmful manner wherein fabric items are roughly abraded.
To overcome these and other disadvantages that are associated with use of an agitator in a vertical axis washer, alternate means for inputting mechanical energy to the wash load have been contemplated. In particular, some washers have been configured to impart a gyratory or wobbling type motion to the fabric items contained in the washer.
U.S. Pat. No. 5,460,018 to Werner et al., having the same assignee as the present invention, discloses a vertical axis washer having a bottom plate that is mounted for wobbling or nutating motion in the bottom of a wash basket. The movement of the bottom plate imparts mechanical to the clothes during a wash portion of the cycle. This washer is capable of washing clothes using a relatively low quantity of wash liquid and has other beneficial characteristics.
As is common with all washers, at the completion of a wash step, the wash liquid within the washer must be drained. To promote extraction of liquid from the clothes, the wash basket is spun during the drain step in the wash cycle. In order to minimize stresses on the support suspension system for the washer as well as to minimize vibration during spin, it is desirable to have the basket and the clothes disposed therein centered about the rotational axis of the basket.
In the Werner et al. machine, the wash plate disposed at the bottom of the wash basket is supported such that the wash plate axis is at an angle relative to the center axis of the basket. As a result of the angled or canted orientation of the wash plate, the fabric items within the wash basket are typically not uniformly arranged about the center axis of the wash basket. Accordingly, during spin, the clothes within the basket create an off balance load that results in undesirable vibration.
The problem of off-balanced spinning in a washer is addressed in U.S. Pat. No. 4,440,004 to Bochan. In Bochan, the entire basket is canted with respect to a vertical reference axis during the wash portion of the cycle such that the basket is wobbled. However, during spin, the mounting means for the basket shifts the basket from a canted orientation to a vertical orientation wherein the basket axis is co-aligned with the vertical reference axis.
In contrast to the Bochan reference, in the Werner et al. machine the wash basket is fixed in a substantially vertical orientation. During the wash portion of the machine cycle, the bottom plate is driven to gyrate or wobble while the basket is prevented from rotating.
It can be understood, therefore, that the bottom plate type washer of Werner et al. offers many benefits but it is subject to undesirable forces during spin due to the unbalanced arrangement of the clothes in the wash basket. However, this off-balance problem would be substantially reduced if the bottom plate was shifted to a level orientation, having its axis perpendicular to the wash basket axis, prior to the initiation of a high speed spin cycle.